1. Field of the Invention
The present invention relates to a semiconductor laser device and a method of making the semiconductor laser.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2004-179274 discloses a ridge waveguide DFB laser having an InGaAlAs active layer. This laser includes a SiO2 protective film having an opening. This opening is formed as follows. After a ridge structure is formed through the etching of a cladding layer and a contact layer on the active layer, a SiO2 protective film is deposited on the surface of the ridge structure, and then the SiO2 protective film is selectively removed by self alignment to form the opening on the ridge structure. An electrode is formed on the ridge structure, and is in contact with the contact layer through this opening.